Nouveau - Oct 2023 - [PATCH] drm/nouveau/dispnv04: fix a possible null pointer dereference

In nv17_tv_get_ld_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference
on failure of drm_mode_duplicate(). Add a check to avoid npd.

Signed-off-by: Ma Ke <make_ruc2021 at 163.com>
---
 drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 670c9739e5e1..4a08e61f3336 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -209,6 +209,8 @@ static int nv17_tv_get_ld_modes(struct drm_encoder *encoder,
 		struct drm_display_mode *mode;
 
 		mode = drm_mode_duplicate(encoder->dev, tv_mode);
+		if (!mode)
+			continue;
 
 		mode->clock = tv_norm->tv_enc_mode.vrefresh *
 			mode->htotal / 1000 *
-- 
2.37.2

On 10/7/23 05:23, Ma Ke wrote:
> In nv17_tv_get_ld_modes(), the return value of drm_mode_duplicate()
> is assigned to mode, which will lead to a NULL pointer dereference
> on failure of drm_mode_duplicate(). Add a check to avoid npd.
> 
> Signed-off-by: Ma Ke <make_ruc2021 at 163.com>
Reviewed-by: Danilo Krummrich <dakr at redhat.com>
> ---
>   drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> index 670c9739e5e1..4a08e61f3336 100644
> --- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> +++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> @@ -209,6 +209,8 @@ static int nv17_tv_get_ld_modes(struct drm_encoder
*encoder,
>   		struct drm_display_mode *mode;
>   
>   		mode = drm_mode_duplicate(encoder->dev, tv_mode);
> +		if (!mode)
> +			continue;
>   
>   		mode->clock = tv_norm->tv_enc_mode.vrefresh *
>   			mode->htotal / 1000 *